Serum-sickness–
like reactions characterized by fever, generalized
lymphadenopathy, arthralgias, and rash occasion-
ally but rarely occur after hymenoptera stings,4-6
but such reactions would be expected to occur more than several hours after exposure and would have resolved over time.

Infections

IM syndrome: EBV, CMV, other herpes virus. IN a immunocompetent host, CMV mononucleosis is similar
to EBV-related disease, though pharyngitis and
cervical lymphadenopathy may be less prominent.

Acute HIV infection:

Autoimmune Conditions:

SLE, RA, Sjogren Syndrome, AOSD, Sarcoidiosis. In SLE lymphondenopathy is common, splenomegaly does not usually occur. Sarcoidiosis may have pulmonary parenchyma disease.

KIKUCHI Lymphadenitis aka histiocytic
necrotizing lymphadenitis. The lymphadenopathy is typically limited to the cervical nodes,
but in rare instances, patients have generalized
lymphadenopathy. Resolution of
Kikuchi’s lymphadenitis occurs spontaneously,
usually within weeks after onset,

Lymphoma: Mostly B cell. 12 % are T cell. Most lymphomas
present sub acutely over a period of weeks to
months, in contrast to the abrupt onset seen in few patients.

Angioimmunoblastic T-cell lymphoma: characteristically presents acutely with diffuse lymphadenopathy and
fever, mimicking an infectious disease, and the
presence of a diffuse, pruritic, maculopapular
rash. Lymphadenopathy is usually not bulky
(1 to 3 cm in diameter), and the swollen lymph
nodes are in the size range seen in inflammatory
or infectious processes, as in this case. The rash
and lymphadenopathy may wax and wane. Up to 80% of patients have
polyclonal hypergammaglobulinemia. Immune dysregulation may
result in the presence of autoantibodies (includ-
ing antinuclear antibodies), rheumatoid factor,
anti–smooth-muscle antibodies, antiphospholipid
antibodies, and false positive serologic tests.